Plotting Vertex arrays in OpenTK

I currently have a vertex array of Vector3's and I am trying to get them to plot on screen The array grows by around 256 points every second but as I redraw my OpenGL screen the array I get huge data gaps on screen and when I look at the array all of the data is there.
Code is below

I am using OpenTK in VB.net

Sructure of my data

Code :

Structure VERTEX
Public position As Vector3
Public colour As Vector4
End Structure